<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript">


        function fun(a,b) {
            alert("有参函数fun(a,b)");
        }

        function fun() {
            alert("无参函数fun()");
        }

        fun(1,"ad");

    </script>
</head>
<body>

</body>
</html>